"We administered intravenous arginine to six patients and six controls to study in vivo inhibition by high ornithine concentrations of arginine-glycine transamidinase, the rate-limiting enzyme in creatine synthesis." (7419715)

Regulatory Information

Regulatory type

Detail

feedback;

"The enzyme was competitively inhibited by ornithine, with a Ki of 0.253 mM. Kidney arginase was inhibited only slightly and non-competitively. Most important in this respect is the feedback repression of AGAT by creatine, the end-product of the pathway. " (7378422)

Defects in GATM are the cause of L-arginine:glycine amidinotransferase deficiency (AGAT deficiency) [MIM:602360]. AGAT deficiency is a defect in creatine metabolism leading to mental retardation [P50440 ];